Cutting apparatus for minimizing deflection of a die cutter assembly

ABSTRACT

A cutting apparatus for cutting a web within a frame includes a die cutter assembly including a cutting blade projecting from a cylindrical surface and a counter anvil including first and second ends journaled into the frame. The counter anvil is positioned below the die cutter assembly for receiving the web fed therebetween across a width of the frame. The cutting apparatus includes first and second outboard bearing assemblies positioned on the die cutter near the first and second opposing ends, respectively, and one or more inboard bearing assemblies positioned about the die cutter assembly and spaced inwardly from the outboard bearing assemblies. Each outboard bearing assembly is configured to control a spacing between the die cutter assembly and the counter anvil along the width of the frame. The cutting apparatus also includes one or more actuators positioned atop the frame in connection with the one or more inboard bearing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to U.S. ProvisionalApplication No. 62/366,210 filed on Jul. 25, 2016, the disclosure ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present subject matter relates generally to rotary die cuttingmachinery. More specifically, the present invention relates to a diecutter assembly that includes one or more inboard bearing housingassemblies that apply pressure along the width of the die cutter throughthe use of air cylinders, pneumatic cylinders, hydraulic cylinders, orany other suitable means.

Die cutting machinery is used in many industries to efficiently andquickly cut a consistent image out of a roll of material such as rubber,cloth, paper, or other low-strength material. Referring to FIG. 1, aconventional rotary die cutting machine 50 includes a cylindricalcutting die 52 and a cylindrical counter anvil 54 rotating in oppositedirections. A long sheet or web 56 of material is fed into the cuttingnip 58 formed by the cutting die 52 and the counter anvil 54, and acutting blade or other tool in the shape of the image formed on thecutting die 52 cuts the web 56 moving through the machine 50. Thecutting speed may range between about 200 and about 450 meters perminute, depending on the materials, the cutting tool, and othercomponents.

During use, cutting forces at the cutting area cause the cutting die toseparate from the counter anvil, creating deflection. On a wide web ofmaterial, pressure is applied near the outer ends of the cutting die,remote from the cutting area and therefore contributing to thedeflection. As the speed increases, the rate at which the cutting forcescreate the deflection increases as well.

Deflection often results in weak or no cuts being made at the cuttingarea as well as an unstable cutting die that bounces on the counteranvil, leading to premature failure. This deflection also causesincreased heat and thermal expansion in the outer bearing housings,further contributing to premature failure.

In some designs, the rotary die cutting machine includes cam followerbearings on the bearing surfaces of the die cutter. However, thebearings are too small for the application, fail prematurely, and arespaced too remotely from the blade to effectively, which causes the diecutter to deflect away from the counter anvil during use. Other designsinclude bearing rings on the counter anvil that are ground to the sameheight as the cutting blade, but these bearing rings often have a lowheat resistance and fail prematurely. Another strategy to counteractdeflection includes bending the counter anvil, but this approach failsto address the thermal expansion of the outer bearings and can damagethe cutting blade if the bend is imprecise.

Accordingly, there is a need for rotary die cutting machinery thatminimizes or eliminates deflection of the cutting die away from thecounter anvil.

BRIEF SUMMARY OF THE INVENTION

To meet the needs described above and others, the present disclosureprovides a die cutter assembly for maintaining constant pressure acrossthe width of a cutting die. The die cutter assembly of the presentapplication includes a cutting blade or other cutting tool positionedalong a surface of the cutting die at a cutting area. First and secondinboard bearing housing assemblies that engage with air cylinders arelocated at midpoints along the width of the cutting die, spaced from thefirst and second ends and adjacent to the cutting area. The inboardbearing housing assemblies apply pressure at midpoints along the widthto maintain a stable, non-deflecting cutting die relative to an adjacentcounter anvil through air cylinders, pneumatic cylinders, hydrauliccylinders, or any other suitable means.

Minimizing deflection of the cutting die allows for increasing machinesspeeds and better control over the materials. In some embodiments, useof inboard air pressure cylinders of the present invention increases themachine speed by as much as 50% to 100%. A stable die cutter also allowsfor cutting of thinner, lower strength materials such as 10 GSM (gramsper square meter) non-woven materials. Increasing the stability of thecutting die also extends the life of the cutting die by reducing theheat and thermal expansion in the outboard bearings, which in turnreduces the interference of the cutting blade into the counter anvil.

In the die cutter assembly of the present application, spacing betweenthe die cutter and the counter anvil is dimensioned to the height of thecutting blade. First and second outboard bearings positioned adjacent tofirst and second ends, respectively, of the die cutter control theheight of the spacing.

The first and second inboard air cylinders apply pressure to the cuttingdie at first and second inboard bearings, respectively. In someembodiments, the cutting area is located centrally along the width ofthe cutting die, and the first and second inboard bearings areimmediately adjacent to the cutting area and spaced from first andsecond ends of the cutting die. In other embodiments, portions of thecutting area are between the first and second inboard bearings whileother portions of the cutting area are closer to the first and secondends of the cutting die.

Over time, the quality of the cut deteriorates as a result of thedeflection of the cutting die. To counter the deflection of the cuttingdie, first and second air pistons of the first and second inboard aircylinders, respectively, apply pressure to the first and secondbearings, respectively. The air pistons may be pneumatic cylinders,hydraulic cylinders, or any device that provides a mechanical loading tothe first and second bearings. Pressure applied to the first and secondinboard bearings may range between about 500 psi to about 5000 psi.

An object of the invention is to provide a die cutting assembly thateliminates deflection while minimizing heat and thermal expansion in theoutboard bearings.

An advantage of the invention is that the assembly results in extendeddie performance and higher cutting speeds.

Additional objects, advantages and novel features of the examples willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing description and the accompanying drawings or may be learned byproduction or operation of the examples. The objects and advantages ofthe concepts may be realized and attained by means of the methodologies,instrumentalities and combinations described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accord withthe present concepts, by way of example only, not by way of limitations.In the figures, like reference numerals refer to the same or similarelements.

FIG. 1 is a schematic of a conventional rotary die cutting machine.

FIG. 2 is a perspective view of a rotary die cutter machine of thepresent application.

FIG. 3 is cross sectional view of the die cutter machine generally takenalong lines 3-3 of FIG. 2.

FIG. 4 is a perspective view of a die cutter assembly of the presentapplication.

FIG. 5 is cross sectional view of the die cutter assembly generallytaken along lines 5-5 of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 2 and 3, the rotary die cutting machine 100 of thepresent application includes a die cutter assembly 102 and a counteranvil 104 mounted within a frame 106. A die cutter 108 of the die cutterassembly 102 includes a cutting blade 110 located centrally along thewidth of the die cutter 108, although the positioning of the cuttingblade 110 may extend further along the width as necessary or desired.

As shown in FIGS. 3 and 5, the die cutter 108 includes a die sleeve 112mounted or otherwise secured to a die shaft 114. First and second ends116, 118 of the die shaft 114 are journaled into the frame 106 as shownin FIGS. 2 and 3. The die shaft 114 is connected to a motor (not shown)that causes rotation of the die cutter assembly 102.

Referring to FIGS. 3 and 5, first and second outboard bearing assemblies120, 122 of the die cutter assembly 102 including first and secondoutboard bearings 124, 126, respectively, that rotate within first andsecond outboard bearing housings 128, 130, respectively. The Inner races132, 134 of the outboard bearings 124, 126 are mounted to the die shaft114, and outer races 136, 138 of the outboard bearings 124, 126 aremounted to the outboard bearing housings 128, 130.

The elevation of the die cutter assembly 102 is controlled by adjustingthe elevation of the outboard bearing housings 128, 130. Best seen inFIG. 3, the outboard bearing assemblies 120, 122 control the verticalspacing 139 of the die cutter assembly 102 and the counter anvil 104,and are adjusted based on the blade height and the amount of deflectionto be countered.

Referring to FIGS. 3-5, first and second inboard bearing assemblies 140,142 positioned along the width of the die cutter 108 are spaced inwardlyfrom the first and second ends 114, 116, respectively, of the die cutter108. First and second actuators 144, 146 positioned atop the frame 106apply pressure to the die cutter 108 through the first and secondinboard bearing assemblies 140, 142. First and second inner bearings148, 150, respectively, rotate within first and second inboard bearinghousings 152, 154, respectively, of the first and second inboard bearingassemblies 140, 142. The inner races 156, 158 of the inboard bearings148, 150 are mounted to the die shaft 114, and the outer races 160, 162of the inboard bearings 148, 150 are mounted to the inboard bearinghousings 152, 154.

As shown in FIGS. 2 and 3, the first and second actuators 144, 146include first and second piston rods 145, 147, respectively, thatcontact the first and second inboard bearing housings 152, 154,respectively. Activation of each actuator 144, 146 applies downwardpressure through the first and second piston rods 145, 147 to theinboard bearing housings 152, 154. In some embodiments, the first andsecond inboard bearing assemblies 140, 142 are positioned immediatelyadjacent to the cutting blade 110. While the outboard bearing assemblies120, 122 control the spacing 139 between the die cutter assembly 102 andthe counter anvil 104, the profile of deflection may vary along thewidth of the frame 102, particularly at the cutting blade 110. Use ofthe actuators 144, 146 through the inboard bearing assemblies 140, 142directs the pressure to the area experiencing the most deflection—thecutting blade 110. The actuators 144, 146 may be any suitable mechanicaldevice for applying pressure to the first and second inboard bearingassemblies, such as air cylinders, hydraulic cylinders, and/or pneumaticcylinders.

The pressure applied through each of the first and second actuators 144,146 may be equal or different, depending on the profile of deflection,the cutting forces along the width of the die cutter assembly 102, andother such variables. Further, the die cutter assembly 102 may includeany number of inboard air cylinder(s) 144, 146 as required by theapplication, the shape of the cutting blade, the strength of thematerial to be cut, and other variables.

It should be noted that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the present invention andwithout diminishing its attendant advantages.

We claim:
 1. A cutting apparatus including a die cutter assembly forcutting a web, said cutting apparatus comprising: a frame including atop frame surface, a bottom frame surface, a first side frame surfaceand a second side frame surface; first and second inboard bearingassemblies; said die cutter assembly, wherein said die cutter assemblyincludes a die shaft having a sleeve diameter, a first end and a secondend, said first end extends from a first end of said sleeve diameter,said second end extends from a second end of said sleeve diameter, saidfirst end of said die shaft is in contact with and rotatably retained byan inner race of a first bearing of said first inboard bearing assembly,said second end of said die shaft is in contact with and rotatablyretained by an inner race of a second bearing of said second inboardbearing assembly; said die cutter assembly further including a diecutter on said sleeve diameter, and said die cutter including a cuttingblade; a first actuator and a second actuator retained on said top framesurface, a moving end of said first actuator is engaged with said firstinboard bearing assembly, a moving end of said second actuator isengaged with said second inboard bearing assembly; a first outboardbearing assembly mounted to said first side frame surface, said firstoutboard bearing assembly rotatably retains said first end of said dieshaft relative to said first side frame surface; a second outboardbearing assembly mounted to said second side frame surface, said secondoutboard bearing assembly rotatably retains said second end of said dieshaft relative to said second side frame surface; and a counter anvilhaving opposing ends rotatably retained in first and second side framesurfaces, wherein outer surfaces of said first and second inboardbearing assemblies do not contact said counter anvil, and wherein a webis locatable between said die cutter and said counter anvil to cut aplurality of parts from the web.
 2. The cutting apparatus of claim 1,wherein said die cutter includes a die sleeve retained on said sleevediameter, and said cutting blade is formed on an outside surface of saiddie sleeve.
 3. A cutting apparatus including a die cutter assembly forcutting a web, said cutting apparatus comprising: a frame including atop frame surface, a bottom frame surface, a first side frame surfaceand a second side frame surface; first and second inboard bearingassemblies; said die cutter assembly, wherein said die cutter assemblyincludes a die shaft having a sleeve diameter, a first end and a secondend, said first end extends from a first end of said sleeve diameter,said second end extends from a second end of said sleeve diameter, saidfirst end of said die shaft is in contact with and rotatably retained byan inner race of a first bearing of said first inboard bearing assembly,said second end of said die shaft is in contact with and rotatablyretained by an inner race of a second bearing of said second inboardbearing assembly, a diameter of said first and second ends of said dieshaft is less than said sleeve diameter of said die shaft; said diecutter assembly further including a die cutter on said sleeve diameter,and said die cutter including a cutting blade; a first actuator and asecond actuator retained on said top frame surface, a moving end of saidfirst actuator is engaged with said first inboard bearing assembly, amoving end of said second actuator is engaged with said second inboardbearing assembly; a first outboard bearing assembly mounted to saidfirst side frame surface, said first outboard bearing assembly rotatablyretains said first end of said die shaft relative to said first sideframe surface; a second outboard bearing assembly mounted to said secondside frame surface, said second outboard bearing assembly rotatablyretains said second end of said die shaft relative to said second sideframe surface; and a counter anvil having opposing ends rotatablyretained in first and second side frame surfaces, wherein outer surfacesof said first and second inboard bearing assemblies do not contact saidcounter anvil, and wherein a web is locatable between said die cutterand said counter anvil to cut a plurality of parts from the web.
 4. Thecutting apparatus of claim 3, wherein said die cutter includes a diesleeve retained on said sleeve diameter, and said cutting blade isformed on an outside surface of said die sleeve.
 5. A cutting apparatusincluding a die cutter assembly for cutting a web, said cuttingapparatus comprising: a frame including a top frame surface, a bottomframe surface, a first side frame surface and a second side framesurface; first and second inboard bearing assemblies; said die cutterassembly, wherein said die cutter assembly includes a die shaft having asleeve diameter, a first end and a second end, said first end extendsfrom a first end of said sleeve diameter, said second end extends from asecond end of said sleeve diameter, said first end of said die shaft isin contact with and rotatably retained by an inner race of a firstbearing of said first inboard bearing assembly, said second end of saiddie shaft is in contact with and rotatably retained by an inner race ofa second bearing of said second inboard bearing assembly, said firstinboard bearing housing assembly is located adjacent said first end ofsaid sleeve diameter, said second inboard bearing housing assembly islocated adjacent said second end of said sleeve diameter; said diecutter assembly further including a die cutter on said sleeve diameter,and said die cutter including a cutting blade; a first actuator and asecond actuator retained on said top frame surface, a moving end of saidfirst actuator is engaged with said first inboard bearing assembly, amoving end of said second actuator is engaged with said second inboardbearing assembly; a first outboard bearing assembly mounted to saidfirst side frame surface, said first outboard bearing assembly rotatablyretains said first end of said die shaft relative to said first sideframe surface; a second outboard bearing assembly mounted to said secondside frame surface, said second outboard bearing assembly rotatablyretains said second end of said die shaft relative to said second sideframe surface; and a counter anvil having opposing ends rotatablyretained in first and second side frame surfaces, wherein outer surfacesof said first and second inboard bearing assemblies do not contact saidcounter anvil, and wherein a web is locatable between said die cutterand said counter anvil to cut a plurality of parts from the web.
 6. Thecutting apparatus of claim 5, wherein said die cutter includes a diesleeve retained on said sleeve diameter, and said cutting blade isformed on an outside surface of said die sleeve.